JPS60232832A - Method of manufacturing block for belt driven stepless speed change gear - Google Patents

Abstract

PURPOSE:To manufacture a block for a belt driven stepless speed change gear, having excellent durability by mass production by employing a process consisting of a blanking of outer form from a plate type steel member, a hardening heat treatment, a shot-blast treatment for an end face, etc. CONSTITUTION:In the manufacturing method of the captioned block, first, a belt type metal belt is punched into the outer form of a block 4 with a press, which is, quenched and tempered to have a hardness above Hv700. Then, the end faces 4a of the block are shot blasted with an abrasive grain having a diameter of 860-2,000mu and molten alumina, forming a surface roughness with a depth of approx. 20mu. The projections of the surface roughness when it is left as shot blasted, are very sharp, which, however, can be removed by carrying out a barrel finishing, to be finished to have an approx. 50% smooth surface. Thereby, the block can have an excellent durability and can be manufactured by mass production.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a block for a heald-driven continuously variable transmission. A block for a belt-driven continuously variable transmission that has excellent durability by punching out the external shape from a shaped steel member, hardening heat treatment, John blasting treatment on the end face, and barrel finishing, and can be manufactured in mass production. It depends on the manufacturing method.

[Prior art]

Continuously variable transmissions can continuously control the gear ratio of the transmission, making full use of the characteristics of the engine and improving exhaust gas and fuel efficiency.

In general, continuously variable transmissions are classified into fluid type, mechanical type, electric type, etc., but fluid type and mechanical type are mostly used for vehicles, and among these, hydraulic drive.

Belt drives and fluid torque converters are the main ones.

As shown in FIGS. 1 and 2, the transmission section of the belt-driven continuously variable transmission consists of an input pulley 1 and an output pulley 1, which can make the diameter of the belt 3 variable by a hydraulic mechanism (not shown). It consists of a pulley 2 and a belt 3 that transmits the power of the input pulley l to the output pulley 2.

Furthermore, the belt 3 is connected to the input pulley 1. Output side boo IJ
A hoop 5 formed by laminating a plurality of endless metal bands hung like a belt between 2, and an input pulley 1. A large number of blocks 4 that have a hoop groove opened opposite the sliding surface of the output pulley 2, are slidable in the width direction of the hoop 50 through this hoop groove, and are arranged continuously. A hoop 5 made of 5 to 15 endless metal strips stacked in a layered manner is fitted into the hoop groove.

In addition, the block 4 and the input pulley 1. are attached to the block end surface 4a which makes sliding contact with the sliding surfaces of the input pulley I and the output pulley 2 of the block 4 used in the belt 3. Surface irregularities are formed in order to adjust the relative coefficient of friction with the sliding surface of the output pulley 2 (for example, Japanese Patent Application No. 53-174).
7).

By the way, in a belt-driven continuously variable transmission, the belt 3
The block 4 used for this is pressed against the input pulley 1 and transmits torque to the output pulley 2 by connecting the block end face 4a and the input pulley l.

If the coefficient of friction relative to the sliding surface of the output pulley 2 is low, the belt 3 may slip.

This slip of the heald 3 not only reduces the transmission efficiency but also causes the belt 3 and the input pulley 1° and the output side boot I.
J2 has the disadvantage of causing damage such as scuffing.

On the other hand, block 4 and input side boo 1J1. Output side pulley 2
If the coefficient of friction relative to the sliding surface of 1.
This has the disadvantage that the life of the output pulley 2 is shortened.

From the above, it can be seen that the block end face 4a and the input pulley 1.
It is necessary to keep the friction coefficient relative to the sliding surface of the output pulley 2 within an appropriate range.For this reason, as a countermeasure to this problem, conventionally the block end face 4a is subjected to shot blasting to reduce its surface roughness. Attempts have been made to adjust the relative coefficient of friction by coarsening the friction coefficient.

However, in the case where the block end face 4a remains shot-blasted (conventional method), as is clear from the durability test results shown in FIG. 5, the block end face 4a and the input side boot IJ1. Output side pulley 2
It has become clear that surface fatigue causes damage and rapid wear.

The reason for this is that the block end face 4a has sharp surface irregularities when shot blasted. It is thought that this is because a slight excessive stress is generated on the sliding surface of the output pulley 2.

As a countermeasure for this, it is known that the most effective way to reduce the contact stress is to provide a smooth part at the tip of the uneven surface of the block end face 4a. There was a problem that it was not possible to form the part stably.

[Purpose of the invention]

The present invention has been made in order to solve the problems of the prior art as described above, and it is possible to create a block for a held drive type continuously variable transmission by punching the outer shape from a plate steel member, hardening heat treatment, and cutting the end face.・Throat blast treatment.

The object of the present invention is to provide a method for manufacturing a held drive type continuously variable transmission gear which has excellent durability and can be manufactured in mass production by using a process consisting of barrel finishing.

[Structure of the invention]

According to the present invention, such objects include: a step of punching out a plate-shaped steel member in a manner adapted to the external shape of a block for a heald-driven continuously variable transmission; and hardening at least a surface portion of the block. A hardening heat treatment step, and a grain size of 0.5 on the end face of the block. A process of shot blasting ~3 fl of hard ceramic particles such as molten alumina powder and silicon carbide powder to form surface irregularities of 10 to 100 microns; This is achieved by a method for producing a block for a belt-driven continuously variable transmission, which comprises a step of barrel finishing in a barrel container containing a mixture of lump or powdered grinding powder, compound, and water.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings.

FIG. 3 shows the manufacturing process of block 4 according to one embodiment of the present invention.

In this embodiment, the material of the block 4 is JIS standard 5U.
This is an example when J2 (bearing li) is used.

In the method of the present invention, first, a metal band is punched into the outer shape of the block 4 using a press, and then subjected to quenching and tempering treatment to harden it to a hardness of v700 or higher.

Next, abrasive grain size: 860-2000 μ, abrasive grain: fused alumina, spraying distance: 50 m, spraying at air pressure: 4-5
Kg/cm2. The spraying time is 60 seconds, and the block end face 4a is shot blasted for about 2 seconds.
A surface unevenness of 0μ was formed.

The surface unevenness of the end face 4a of the block after shot blasting in this manner is shown in FIG. 4fa).

As is clear from this figure, it can be seen that the protrusions of the surface irregularities are sharply pointed in the shot-blasted state.

Then, block 4 was coated with barrel abrasive; alumina.

Barrel abrasive shape: φ5X15mm, compound;
The alkaline compound and rust preventive water were mixed and sealed in a barrel container, rotation speed: 20 rpm, processing time;
Barrel polishing was performed for 5 hours.

The surface unevenness of the block end face 4a after barrel polishing is shown in FIG. 4(b).

As mentioned above, the protrusions on the surface unevenness were very sharp after shot blasting, but by performing barrel finishing, the sharp protrusions at the tips disappeared and the surface was approximately 50% smooth. I was able to finish it.

Three blocks 4 for a belt-driven continuously variable transmission of the present invention manufactured in this way were each assembled into a belt-driven continuously variable transmission, and the rotation speed: 3500 rpm, input torque: 16
A durability test was conducted for 150 hours under the following conditions: Kg-m, gear ratio: 2.

The test results are shown in FIG.

As is clear from this test result, the block 4 for a heald-driven continuously variable transmission manufactured by the conventional method has significant wear accompanied by fatigue, whereas the block 4 for the held-driven continuously variable transmission manufactured by the method of the present invention We were able to confirm that the block had little wear and no rapidly progressive surface damage.

It goes without saying that by shortening the barrel finishing time, it is possible to lower the area ratio of the smooth surface at the tip that dissolves into the uneven surface shape of the block end face 4a.

[Function and effect of the invention]

As is clear from the above, according to the method for manufacturing a block for a belt-driven continuously variable transmission according to the present invention, the block for a belt-driven continuously variable transmission is punched out from a plate-shaped steel member, hardened, etc. By using a process consisting of heat treatment, shot blasting on the end face, and barrel finishing, there is an advantage that it has excellent durability and can be manufactured in mass production.

In addition, in the block for a heald-driven continuously variable transmission manufactured by the method of the present invention, it is possible to remove metal particles that are likely to fall off from the valleys of the uneven surface of the end face of the block, so that the falling particles can be removed from the input side. There is an advantage in that it is possible to prevent the occurrence of local excessive stress that would otherwise occur if the pulley is interposed between the output pulley and the block.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a transmission section of a heald drive type continuously variable transmission. FIG. 2 is a perspective view showing how the hoop and block are assembled. FIG. 3 is a diagram showing the manufacturing process of a block for a belt-driven continuously variable transmission according to the method of the present invention. FIG. 4 is a diagram showing the surface unevenness shape of the end face of the block. FIG. 5 is a diagram showing the durability test results of blocks for a Herd drive type continuously variable transmission manufactured by the conventional method and the method of the present invention. 1-11--Input end pulley. 2-------~ Output side pulley. 3-----Held. 4----Block. 4a------Block end face. 5--1~-Hoop. Applicant Toyota Motor Hobun Company Figure 1 Figure 2

Claims (1)

[Scope of Claims] (2) A step of punching out a plate-shaped steel member in a manner that matches the external shape of a block for a belt-driven continuously variable transmission, and a hardening heat treatment step of hardening at least a surface portion of the block; A process of shot blasting hard ceramic particles such as molten alumina powder or silicon carbide powder with a particle size of 0.5 to 3 on the end face of the block to form a surface unevenness of 10 to 100 μ; A method for manufacturing a block for a belt-driven continuously variable transmission, which comprises the step of finishing a barrel in a barrel container in which a mixture of lump or powder polishing powder of ceramics such as quartz or silica sand, a compound, and water is sealed.